Bomb bay positions

[PMN1]

A large number of the RAF Bomber designs (ones that stayed design projects as well as those that entered service) carried a significant portion of their bombload in wing bays – what was the advantage of this?

Apart from the Consolidated PB2Y Coronado, US bombers seemed to carry all their bombload in fuselage bomb bays, what was the objection on the US side to wing bomb cells?

[simon]

I think the explanation for this stems from the difference in the pre-war doctrines between the two air forces.

The British led by the theories of Trenchard and Douhet were firm believers in the concepts of terror bombing. Against a target like a family house or an appartment block a hit or even a near miss with almost any kind of military ordinance would cause damage and fatalities and pretty quickly the population would be induced to revolt against their rulers, who would then be forced to sue for peace (So the theories go, the practicalities of this were somewhat different).

With this in mind it stands to reason therefore that aircraft like the Stirling were designed to carry a large quantity of bombs rather than overall weight, or even a decent individual bomb weight. The logic is simple. If you design a bomber to carry 4,000lbs of bombs (for example) you'll hit far more targets than with 100 x 40lb bombs than with 4 x 1,000lb bombs. This does fall down somewhat when you consider that against an industrial target you'll be far more likely to cause damage to the target with a single 1,000 pounder than you would with the full weight of 40 pounders.

So aircraft like the Stirling where basically designed for area / terror bombing, and if you're designing an aircraft if you have to cram the maximum number of bombs (Regardless of weight) into the airframe, once you start running out of fuselage about the only place left to put them is in the wings.

The US however were great believers in high accuracy bombing against industrial and "Bottleneck" targets. They appreciated, although not fully until this was tested in operations, that fewer, heavier bombs dropped with greater accuracy are more likely to damage the intended target than saturating the area with tiny bombs. So if you're designing a bomber with this in mind, you're far less likely to run out of fuselage to begin with, and even if you do carrying these larger bombs in or even externally under the wings is a far less practical or desirable option.

Another question that was asked in an earlier thread, which I'm just too lazy to go back and find was about the 100ft wing span limitation. I believe that this was dropped because it became obvious that it was going to limit the performance and especially the ceiling of aircraft too much, this became really apparent with the Stirling. I think the Air Ministry finally appreciated that the better option was just to build bigger hangars!

[PMN1]

quote:Originally posted by simon



The British led by the theories of Trenchard and Douhet were firm believers in the concepts of terror bombing. Against a target like a family house or an appartment block a hit or even a near miss with almost any kind of military ordinance would cause damage and fatalities and pretty quickly the population would be induced to revolt against their rulers, who would then be forced to sue for peace (So the theories go, the practicalities of this were somewhat different).

Another question that was asked in an earlier thread, which I'm just too lazy to go back and find was about the 100ft wing span limitation. I believe that this was dropped because it became obvious that it was going to limit the performance and especially the ceiling of aircraft too much, this became really apparent with the Stirling. I think the Air Ministry finally appreciated that the better option was just to build bigger hangars!


Have you read 'Bomber Command by Max Hastings - there is a paragraph in there where in 1917 Churchill, when he was Minister of Munitions, dismisses the arguments for terror bombing before Trenchard etc had even developed them. I think if this had been listened to, we could have seen a RAF bomber force more like Germany's i.e. more dedicated to supporting the Army. Whilst this would have been useful in the early stages of the war I guess we would have suffered the same problems with regard to the ability to carry out heavy bombing that the Germans did.

With the extra wingspan the beneficial effect on performance was quite high, if you look at the B1/39 spec all of which were designed WITHOUT the limitation right from the start, you see cruising speeds of 260 - 280mph and max speeds of 280 - 340mph on wingspans of 109ft to 133ft with Griffin or Hercules engines.

[simon]

I haven't read it, although it's been on my "Must buy" list for a while I just haven't found time to get around to it.

Along the same lines, it has to be said that Paul Brickhill's "The Dambusters" is also excellent, if you haven't read this then it's a must.

I think the RAF's stance on area and Terror bombing was an unfortunate necessity to avoid it being reabsorbed by the Army and Navy in the twenties and thirties, the argument used at the time (Infact it is still being seriously suggested that the RAF as a separate entity is unnescessary!) was that if the RAF was to be an adjunct to the army in the same way the Luftwaffe became, then it may as well be a direct part of the army.

So the RAF concentrated on pushing the strategic, area/terror bombing role for itself and the rest is history.

[B-24WillowRun]

AS for the bomb load in wing bays remember that the aircradt that used them are for the most part with the USAAF that it, Amphibians. So it is a more practical matter.

As for the 100 foot limit. That was a problum with the Halifax I think in the beginning. But it was fixed. I am not shure if the RAF would have been more like the German Airforce in being able to support the army. But the war played out that haveing a balance of both long range and tatical or mid range was the best. Though the P.108 would have been able to chase Russia over the mountains.

[PMN1]

The long unobstructed bomb bay of the Manchester, Lancaster and Halifax was due to the P13/36 requirement for the aircraft to carry 4 (later reduced to 2) torpedoes.

How many of the standard 250lb, 500lb and 2,000lb bombs that the Stirling and other B12/36 designs were designed around could be carried in this bomb bay.

Could the Stirling and other B12/36 designs have carried the required number of 250lb, 500lb and 2,000lb bombs if their bomb bays were the same as the Manchester, Lancatsre and Halifax.

[PMN1]

quote:Originally posted by simon

Along the same lines, it has to be said that Paul Brickhill's "The Dambusters" is also excellent, if you haven't read this then it's a must.


Intresting read - makes you wonder what could have been done if the Tallboy and Grand Slam had been available earlier (and the aircraft to carry them)

[GregP]

I have no idea why the British chose to use wing bomb bays. It defies logic.

Fuel stored in the wings has a damping effect on wing oscillation, and fuel burns from the tip inward. Any remaining fuel is located near the wing roots, offering wing damping. Bombs stay there until dropped, and then the wing loses its damping mass that the bombs afforded in rough air.

So, a bomber which carries bombs in wing bomb bays will be weaker on the way home in rough air than one with fuel in the wings. Simple structural design.

Also, the fuselage offers a much larger vertical volume for bomb storage than the wing, and the main concentration of weight can be stored near the center of gravity, or CG. CG considerations drove WWII bomber design to a very large degree.

[simon]

It doesn't defy logic Greg, the logic is there in my initial reply, it's all down to the pre-war doctrines, and if you look at the wing bays on the Stirling they're really quite small compared to the wing area but big enough to fit a couple of smallish bombs in.

The Logic and Doctrine were flawed is also true, however they were widely accepted at the time.

[B-24WillowRun]

Even if all that is flawed docterine or they made sence, the wing bays did not offer for a veriety of ordinance. Though that I gess was made up with the long bomb bays. But what confuses me with the wing bays on aircraft other then the sea planes, is that they are more vulnerable to attack. This is very true on the way into the target. Any one have thoughts on that?

Simon, nice job about the fuel burn.[8D]

[GregP]

Hey, I didn't say that wing bombays were a BAD idea, I said they were flawed and defied logic. I stand by that statement. Wing bomb bays were a waste of available fuel space, and were not optimized for bombing. Were they completely ineffective? No.

Bombs dropped from them DID do some damage.

Just commenting on the relative wisdom of the subject. It was less -than-smart, and is stupid today. No on uses it in modran aerial warfare.

[PMN1]

quote:Originally posted by simon

It doesn't defy logic Greg, the logic is there in my initial reply, it's all down to the pre-war doctrines, and if you look at the wing bays on the Stirling they're really quite small compared to the wing area but big enough to fit a couple of smallish bombs in.

The Logic and Doctrine were flawed is also true, however they were widely accepted at the time.



The Shorts Stirling (B12/36) could carry 24 x 500lb bombs three side by side in its 42ft bomb bay (longer than the Lancaster and Halifax). The largest bomb which could be carried was the 2,000lb AP which was same width but longer. There were 12 wing cells, which I think could each only carry a single 500lb bomb.

The Supermarine Type 316 bomber design to spec B12/36 would have suffered from the same problem as the Short Stirling as far as bombload was concerned – Rather than one big bomb bay it had a small fuselage bomb-bay with extra bomb "cells" in the wings - The total bombload was a respectable 14,000 lb - but no single bomb could be bigger than 2,000 lb - So the big 4,000 8,000 and 16,000 lb bombs carried by the Lancaster would have been impossible for the Supermarine bomber to carry. The Fuselage bomb bay could accommodate either 3 x 2,000 lb bombs or 9 x 500 lb bombs or 9 x 250 lb bombs. Each wing had 10 bomb "cells" - 20 in all - The two cells on each wing nearest the fuselage could accommodate a 2,000 lb bomb, meaning that a total of 7 x 2,000 lb bombs could be carried (giving the maximum bombload of 14,000 lb). The next 7 cells could accommodate a 500 lb bomb each, while the furthest cell out could only hold a 250 lb bomb. Each of the larger bomb cells could accommodate a smaller bomb if needed - Thus if every cell held a 250 lb bomb and the fuselage bomb bay was loaded up with 9 x 250 lb bombs you would end up with a total of 29 x 250 lb bombs.

The unchosen Armstrong Whitworth proposal for B12/36 had a similar arrangement and given the RAF requirement of the day I would assume the Bristol, de Havilland and Vickers Armstrongs proposals would be roughly the same.

It was the requirement to carry torpedoes that resulted in the Manchester/Lancaster and Halifax having the large unobstructed bomb bay.

This large number of smaller bombs was carried over into the B1/39 ‘Standard Bomber’ spec – 20 x 250lb or 500lb, 10 x 1,000lb or 5 x 2,000lb AP – on this design the position of the ventral quad 20mm turret would seem to rule out a long fuselage bomb bay on most of the designs I’ve seen – the Vickers Armstongs proposal being an exception.

[B-24WillowRun]

PNM1- that was a nice leason, where did you get the resurch? I have read a little on the bombers, but not as much on the ones not built. I am trying to get Halifax history and information.

Thanks again i hope we can keep talking.:)

[PMN1]

quote:Originally posted by B-24WillowRun

PNM1- that was a nice leason, where did you get the resurch? I have read a little on the bombers, but not as much on the ones not built. I am trying to get Halifax history and information.

Thanks again i hope we can keep talking.:)


A combination of James Goulding and Philip Moyes's RAF Bomber Command and its aircraft 1936 - 1940 and 1941 - 1945 (which incidently questions the logic of wing bomb cells as GregP did above), John Dell

http://myspace.virgin.net/john.dell/

and searching the net.

[B-24WillowRun]

I tock a look at the website. I was really interested in the B20, that would have been a sight to see.

[PMN1]

Just checked again and the Stirling had 6 wing cells total, not 6 ineach wing.

These were plumbed for auxiliary fuel tanks, not sure about the fuselage cells.

[PMN1]

[/quote]

Intresting read - makes you wonder what could have been done if the Tallboy and Grand Slam had been available earlier (and the aircraft to carry them)
[/quote]

Found an interesting site on the Tallboy, Grand Slam, US 42,000lb and US 25,000lb bombs

http://members.aol.com/nukeinfo2/

[simon]

I'm reminded of a conversation I had with an RAF ATCO about 10 years ago. He commented that the Tornado can carry a bigger bombload, further and faster than the Lancaster.

My reply was that the Tornado couldn't have done that in 1942.

If the Bf109 had been available in 1915 the airwar over the trenches would have taken a distinct turn in the Imperial Air Force's favour, such discussions can only ever be relative to the technology available at the time and unfortunately Barnes Wallis was thinking years ahead of his contemporaries.

Aside from that the link is impressive, a 42+K lber is terrifying when you consider the results achieved with a Grandslam!

[PMN1]

quote:Originally posted by simon

Aside from that the link is impressive, a 42+K lber is terrifying when you consider the results achieved with a Grandslam!


The quote from the RE officer at Messines ridge in WW1 springs to mind, smoething along the lines of 'I dont know if we will make history but we will certainly make geography':D